"precise enough" is a matter of opinion. If you look at his chart you will see that sub 45 grain bullet group size out of the 1:12 is about 30% smaller than his average out of the 1:7 barrel. The group size for 35 grain bullets out of the 1:12 barrel is about half the size of the group from the 1:7From Andrew Tuohy:
The 1/7 twist barrel did not overstabilize any of the ammunition types. It was remarkably accurate with some of the lighter bullets. Although it generally shot better groups with the heavier projectiles, it was accurate and precise enough with the light bullets for almost any purpose, including varmint hunting.
Again we are back to a 55 grain bullet. 55 grain may be a light bullet to NATO but it is not to varmint hunters.From Molon:
Contrary to some of the nonsense you may have heard around here about fast twist barrels not being able to shoot light-weight bullets accurately, the 10-shot group pictured below was fired from 100 yards using 55 grain BlitzKings from a 1:7.7" twist barrel. While a fast twist barrel is not the ideal twist for light-weight bullets, as you can see from the target below, sub-MOA groups can be obtained with light-weight bullets fired from a fast twist barrel.
People around here seem to be big on the NRA and what they have to say so let's see what they said in the American Rifleman in 2011
Now if you look at the chart from the link you posted would you say that for a prarie dog hunter who likes the ballistics of a 35grain bullet that a 1:7 twist rate is a good choice?With 40- to 50-grain varmint bullets, the .223 Rem. is deadly on prairie dogs, ground squirrels and gophers out past 400 yards. For larger vermin like ground hogs and rock chucks, shooting them inside 300 yards provides a lot more bullet upset due to the higher impact velocities.
Later they say,
In a handloading article Shooting Times had this to say,As a rule of thumb, if the heaviest bullet you will be shooting is 50 grains or less, the 1 in 12 twist should provide good accuracy. If you want to be able to accurately shoot bullets that weigh at least 60 grains, go with the 1 in 9 twist. And finally, if you plan to shoot the really long and heavy bullets, like the Bergers, a twist rate of 1 in 8 or even 1 in 7 is a good idea. For most common use or hunting applications, the 1 in 9 twist is the way to go and will stabilize the light 35- to 40-grain bullets well enough for you to shoot little groups and hit little targets.
So again it comes back to what someone wants the rifle for. If you want a McRifle to shoot milsurp or NATO spec ammo then yes, you can't go wrong with a so called mil-spec rifle. If on the other hand you have a specific purpose for your rifle, like small critter shooting at long range, a mil-spec rifle could be a poor choice.Match rifles in .223 Remington, the AR15 in particular, are available with barre
ls in a variety of rifling twist rates. Making proper choices among the various bullet weights boils down to a simple matter of how slow or quick the rifling pitch is. As a rule, optimum twist rate for bullets weighing 40 to 55 grains is 1:12 inches–although as previously mentioned, some rifles with that twist rate will handle some bullets as heavy as 64 grains.
Read more: Handloading The .223 Remington For The AR15